Sifter device for cleaning grain



Oct. 31, 1967 O LOKEN SIFTER DEVICE FOR CLEANING GRAIN Filed Nov. 14, 1966 3 Sheets-Sheet 1 FIG. 7

INVENTOR OLIVER T. LOKEN ATTORNEY Oct. 31, 1967 o. T. LOKEN 3,349,910

SIFTER DEVICE FOR CLEANING GRAIN Filed Nov. 14, 1966 3 Sheets-Sheet .2

INVENTOR OLIVER T. LOKEN FIG. 5 BY ATTORNEY Oct. 31, 1967 o. T. LOKEN 3,349,910

SIFTER DEVICE FOR CLEANING GRAIN Filed Nov. 14; 1966 3 Sheets-Sheet 5 I INVENTOR H 4 OLIVER T. LOKEN 5 Khm ATTORNEY United States Patent 3,349,910 SHFTER DEVICE FOR CLEANING GRAIN Oliver T. Loken, Rte. 3, Albion, Nebr. 68620 Filed Nov. 14, 1966, Set. No. 594,108 9 Claims. (Cl. 209-245) ABSTRACT OF THE DISCLOSURE This invention relates to apparatuses for removing dirt and other foreign matter from farinaceous grains. In particular this invention relates to a self-powered hopper type grain cleaning device which includes a novel vibrating sifter mechanism component, said sifter mechanism being admirably adapted for use with various types of grain cleaning apparatuses.

This patent application is a continuation-in-part of Ser. No. 386,090, filed July 29, 1964, which in turn was a continuation-in-part of Ser. No. 286,895, filed June 6, 1963, both now abandoned.

Specification During the harvesting processes, corn and other farinaceous grains become mixed with dirt, stones, husks, and other foreign matter. Accordingly, it is necessary to pass the grain-foreign matter mixture through some type of sifting apparatus to separate the grain from the foreign matter. Invariably, the grain cleaning apparatus includes a sifter mechanism comprising a generally horizontal screen or other multi-perforate sieve and a vibratory mechanism therefor. Vibratory mechanisms may cause screen movement in one or a combination of several directions including normally to, parallel to, and obliquely to the general plane of the screen. Inefiiciencies of sifter mechanisms of the prior art stem from the types of vibrations imparted to the screen. A generally necessary auxiliary apparatus for grain cleaning operations is some type of independently powdered auger device to transport the uncleaned grain from a truck dump box or other storage compartment to the storage device. It is many times desirable to transport the grain cleaner apparatus from one grain storage area to the other, and it is frequently necessary to operate the grain cleaner at locations that are permanently or temporarily lacking in independent power facilities.

It is accordingly a general object of the present invention to provide a portable grain cleaner device that may be powered by conventional independent power facilities, and that may be also operated where such conventional power facilities are unavailable.

It is another object of the present invention to provide a sifter mechanism which may be advantageously employed in a variety of grain cleaner apparatuses including those of the stationary type, those of the portable type, and those of the type which may be temporarily attached to the rearward opening of a truck dump box.

It is yet another object to provide a sifter mechanism that has a unique and eflicient vibratory action.

It is a further object to provide a grain cleaner device and a sifter mechanism therefor which may be economically manufactured, repaired,- and maintained utilizing standard, durable, and readily-obtained parts.

With the above and other objects and advantages in view, which will become apparent as the description proceeds, the invention comprises the novel form, combination, and arrangement of parts as hereinafter more fully described, reference being had to the accompanying drawings wherein like numbers refer to like parts in the several views and in which:

FIGURE 1 is a perspective view of a grain cleaner embodying the sifter device of the present invention.

FIGURE 2 is a sectional elevational view of the grain cleaner of the present invention taken along line 22 of FIGURE 1.

FIGURE 3 is a bottom plan view of the grain cleaner of FIGURES 1 and 2 to show particularly the novel sifter mechanism portion thereof.

FIGURE 4 is an alternate type of the sifter device of the present invention.

FIGURE 5 is a sectional elevational view taken along line 5-5 of FIGURE 4.

FIGURE 6 is a front elevational view of a single headed cam which may be employed as a component of the oscillatory driven means for the sifter device.

FIGURE 7 is a front elevational view of a doubleheaded cam which may be employed as a component of the oscillatory driven means for the sifter device.

The grain cleaner A of FIGURES 1-3 comprises a portable hopper 100, a sifter device 10, and means for supplying drive power to the sifter mechanism 10 through a rotatable power shaft 150, said power supply means being as a rotatable paddle wheel 200 or as a separate exterior power source (not shown).

Upright hopper device comprises an upper bin 101 communicating with a lower him 102, by means of intermediate throat 103, said upper bin 101 being forwardly offset with respect to lower bin 102. Lower bin 102 has a bottom panel 104 that slopes obliquely downwardly and forwardly. Lower bin 102 terminates with a vertically disposed outlet spout 105 at the forward side of hopper 100. Upper bin 101 has a horizontally disposed inlet opening 106 at the upper extremity for the introduction of the mixture of grain and wheels 107 attached to opposite sides of lower bin 102 so as to render grain cleaner device A portable. There is a downwardly extending leg 108 attached to the rearward side of lower bin 102, so that device A may be stabilized in position on the terrain.

There are throat-control means to control the amount of precleaned grain permitted to enter lower bin 102 from upper bin 101. Such throat-control means may take the form of a slidable plate 111 resting upon upper panel 112 and extending into the interior of upper bin 101. The degree of extension of slidable plate 111 may be maintained with the combination of slot 113 along plate 111 and threaded bolt 114 passing through panel 112 and slot 113 of plate 111.

The preferredsifter mechanism 10 has utility in several varieties of grain cleaner devices including device A, and sifter device 10 is illustratively shown incorporated into device A in FIGURES 1-3. Sifter device 10 comprises a multi-perforate non-veritcal sieve covering an opening in a frame; a plurality of substantially parallel support rods positioned immediately below the lower surface of the sieve, the respective support rods having a free end and a confined end, the forward portion of the sieve being attached to the support rods; an elongate axle located below and in intersecting relationship with said support rods, said elongate axle being free to revolvably turn in alternate directions about its longitudinal axis; at least one lifter bar uprightly attached to the elongate axle, said lifter bar extending in height toward the support rods; a laterally-extending lever arm attached to said elongate axle, the length of said lever arm being preferably at least four times the height of said lifter bar; and means to supply oscillatory angular motion to the elongate axle about its elongate axis, the angular velocity in one of the two directions being at least twice as great as in the other direction.

An illustrative frame would be the lower portion of lower bin 102. The frame lower opening may be the rec- 3 tangular opening 115 terminating at the rearward extremity of bottom panel 104, and in this situation, the lower portion of lower bin rearward panel 116 is the rearward side of the frame member while the bottom panel 104 at 117 would be the forward side of the frame.

A multi-perforate sheet-like sieve 11 is disposed across opening 115 and substantially covers the entire opening so as to act as a barrier to restrain grain from falling between opening 115 and sieve 11. Sieve 11 may be of the woven screen type shown in the drawing or alternatively any other type of multi-perforate sheet having a perforation size intermediate to the particle size of the grain to be cleaned and the finer foreign matter to be separated therefrom. Screen 11 has an upper surface, a lower surface, a first side edge at 12, a second side edge at 13, a rearward edge at 116, a forward edge at 117, and a transverse axis E. Screen axis B is positioned between screen side edges 12 and 13, and said axis E extends between the forward and rearward edges of screen 11. Screen 11 may desirably assume the substantially planar configuration shown in the drawing. The rearward edge of screen 11 is povitably attached to the rearward side of the frame at 116.

There is a plurality of substantially parallel support rods 20 positioned parallel to and immediately below the lower surface of screen 11, said support rods 20 being also substantially parallel to screen transverse axis E. While four such support rods 20 are shown in the drawing, any plural number may be so employed. Each of said support rods has a confined or restrained rearward end 21 and a free forward end 22, and said support rods are resiliently deflectable in the upward direction toward screen 11. The forward portion of screen 11 is attached, as by wires, to the several support rods 20, and thus, as rods 20 are made to deflect upwardly, screen 11 will upwardly deflect in like manner. It is desirable that there be means to limit the degree of upward deflection for screen 11 and rods 20 so that the cleaned grain flow toward the outlet eg 105, is not unduly impeded. Accordingly, it has been found desirable to utilize fairly rigid, yet resiliently flexible, rods 20 and to rigidly fix the rearward end 21 of rods 20 at frame rearward side e.g. 116. For example, said rods 20 may pierce and be attached to the lower extremity of lower bin rearward panel 116, and thus, the several support rods 20 act as cantilever supports for screen 11.

There is an elongate anchor rod 30 attached to the lower side of the several support rods 20. Linear anchor rod 30 is substantially normal to the several support rods 20 and to screen transverse axis E. Anchor rod 30 is positioned nearer to rods free ends 22 than to restrained ends 21, and preferably, anchor rod 30 is at least two thirds the distance from restrained ends 21 to free ends 22.

There is an elongate linear axle 40 that is substantially parallel to anchor rod 30 and is substantially normal to the several support rods 20 and to screen transverse axis E. Axle 40 is attached with suitable bearings 41 to the frame member e.g. at bottom panel 104, so that axle 40 will revolvably turn about its elongate axis in both directions, at least to a limited extent in both directions.

Beyond the sideward confines of the screen and the frame 104 there is a laterally extending lever arm 45 attached to elongate axle 40. As will be explained later in greater detail, lever arm 45 causes reciprocating i.e. oscillatory, axial turning of the axle 40 and the at least one lifter bar 50 so as to vertically vibrate or agitate support bars 20 and screen 11 in a direction substantially normal to sieve 11.

There is at least one lifter bar 50 attached to axle 40, and extending in height from axle 40 toward support bars 20 so as to cause resilient upward deflection of said support bars 20 and screen 11. As shown in FIGURES 1-3, there may be three equal-length lifter bars 50, each lifter bar 50 being of sufiicient height for the free ends 51 to strike anchor rod 30 when axle 40 is oscillated in short angular movements about its longitudinal axis. The extent of oscillatory angular movement is desirably as small as possible and should not exceed 270, and preferably not exceeding The length of lateral arm 45 exceeds the height of the at least one lifter bar by a factor of at least 3, and preferably, the leverage ratio is about 4 to 1.

There are means to impart oscillatory axial angular movement i.e. twisting, to said elongate axle 40, the twisting speed is one of the two directions being at least twice as great as in the other direction so that sieve 11 will vibrate at a greater speed in one direction than in the other. For example, sieve 11 might move twice as fast in the downward direction than in the upward direction so that foreign matter can be shaked from the grain and sifted through sieve 11. Preferably there is an abrupt change in direction of sieve 11 at its upward limit of travel. The oscillation control for axle 40 may employ a cam having the configuration shown in FIGURES 6 and 7 mounted along powered shaft 150, said cam bearing against lever arm 45. There are means to cause lever arm 45 to bear upon or ride along the cam, and such means may take the form of a spring 46 connected between lever arm 45 and a strut 109 attached to the forward side of lower bin 102. The cam employed might be the single-headed type 60 of FIGURE 6 or the double-headed type 70 shown in FIGURE 7. The contour of both cams do include two surfaces 61 and 62 and an abrupt boundary or discontinuity 63 between surfaces 61 and 62. Surface 61 is gently convexly curved so as to provide a slower degree of turning motion in axle 40 in one of its two alternate directions. However, when boundary point 63 of the cam is brought to bear against lever arm 45 followed by relatively flat surface 62, the direction of travel for arm 45 is sharply reversed, thus turning axle 40 abruptly in the opposite direction. The contour of earns 60 and 70 are effectively identical and cause the same type of reciprocating variable-speed turning action of axle 40. However, cam 70 is double-headed and causes twice the response frequency in axle 40 with every turn of powered shaft 150.

Shaft may be powered in several convenient ways. An exterior power source can be applied to a pulley 151 on shaft 150, said power might conceivably be transmitted from the shaft of an auger used to deliver precleaned grain to inlet spout 106.

Shaft 150 might be powered solely from the kinetic energy of the pre-cleaned grain falling from upper bin 101 to lower bin 102. In this event, a paddle wheel 200 having a plurality of radially protruding fins is attached in fixed rotational relationship along shaft 150 Within the confines of lower bin 102. In order to insure that the paddle wheel 200 will deliver the falling pre-cleaned grain to the rearward end of sloping screen 11 to provide efficient grain cleaning (or foreign matter separation through screen 11) it is essential that the pre-cleaned grain strike the paddle wheel at a point rearwardly of the paddle wheel vertical axis V. To insure the delivery of pre-cleaned grain rearwardly of vertical axis V, upper bin forward panel 122, or separate rearward chute-like extension thereof, must have its terminus rearwardly of axis V. Preferably, the pre-cleaned grain is directed rearwardly of axis V with a slidably adjustable chute-like plate 123 that rests upon panel 122 within the interior of hopper device 100. The degree of extension for slidable interior plate 123 may be controlled with the combination of slot 124 along plate 123 and threaded bolt 114 passing through rearwardly and downwardly sloping panel 122 and slot 124 of slidable plate 123. With the paddle wheel type power means for shaft 150, the double-headed cam contour of FIGURE 7 is preferred because of the relatively slow angular velocity of shaft 150 normally afforded by grain dropping twelve feet or less.

The sifter mechanism 10 previously described within hopper device A will induce or provide a unique vibratory shaking action to screen 11 normal to the transverse axis E thereof. Because of the variable speed imparted to the oscillatory angular movements of axle 40, as afforded by the appropriate cam contour for example, will cause the screen 11 to rise relatively slowly and fall relatively fast thus shaking the dirt and other foreign matter downwardly through screen 11. The so-cleaned grain emerges through outlet spout 105 to a suitable receptacle (not shown).

Sifter mechanism can also be utilized at the rearward end of a truck dump box F for cleaning grain emerging from the rearward end of said dump box, and the truck dump box acts as the frame support for axle 40 and for support rods restrained ends 21.

FIGURES 4 and 5 illustrate an alternate type of sifter mechanism that might be employed within the general concept of the present invention. The restrained end 21 of rods are pivotably attached to frame F as by means of pivot pin passing through rod 20 and a protuberance G on frame F. The upper portion of frame F has a contour at H to limit the degree of upward travel for rods 20. Thus, in FIGURES 1-3 the upward limit of travel for rods 20 is governed by the structural springiness of the rods sincerestrained rod 21 is fixed in cantilever fashion while in FIGURES 4 and 5 the upward limit of travel is governed by frame contour H since restrained ends are pivotal with respect to frame F. The downward resiliency for rods 20 in FIGURES 4 and 5 is controlled by resilient springs S connected between rods 20 nearer to free end 22 and axle 40, whereas in FIGURES l-3 the downward resiliency is provided by the inherent structural springiness or flexible resiliency of rods 20. As can best be seen in FIGURE 5, there is but one lifter bar 55 which extends along a major portion of axle 40. Since elongate lifter bar 55 is Wider than the spacing between transverse bars 20, there is no need for anchor rod as shown in FIGURES 1-3, elongate lifter bar 55 simultaneously striking a plurality of transverse bars 20 directly. The sifter mechanism of FIGURES 13 is definitely preferred over the alternative type of FIGURES 4-5, the alternative type being shown merely to better illustrate the principles of this invention.

From the foregoing, the construction and operation of the sifter device for cleaning grains will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact constructions shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claims.

I claim:

1. A sifter device including a non-vertical multi-perforate substantially planar sieve component, said sieve component being adapted to vibrate in a direction substantially normal to the plane thereof, the vibrating sieve having a greater vibrational speed in one direction than in the other alternate direction, said sifter device comprising:

(A) a substantially planar non-vertical multi-perforate sieve having an upper surface, a lower surface, a forward edge, a rearward edge, a first sideward edge, a second sideward edge, and a transverse axis located between the first and second sideward edges, said axis also extending between the sieve forward and rearward edges,

(B) a frame member, a portion of which extends along the rearward edge of the multi-perforate sieve,

(C) a plurality of substantially parallel support rods positioned below the lower surface of said multiperforate sieve parallel to the lower surface and t0 the transverse axis of said sieve, each of said support rods having a confined end and a free end, the confined ends of the several support rods being attached to that portion of the frame member that extends along the rearward edge of the multi-perforate sieve, the free ends of said support rods being free to move in the upward direction, means to limit the upward direction of travel for said support rods free ends, said multi-perforate sieve being attached to said support rods,

(-D) an elongate axle that is revolvably attached to the said frame member, said elongate axle being positioned below and substantially parallel to the multiperforatesieve, said elongate axle being substantially normal to the support rods and to the sieve transverse axis,

(E) at least one lifter bar attached along the length of the elongate axle and extending in height toward the said support rods so that said at least one lifter bar will impart upward motion to the support rods and sieve when the elongate axle revolves about its elongate axis,

(F) means for imparting oscillatory angular movemen to said elongate axle about its elongate axis such that the extent of angular oscillation is less than 270 degrees and the angular velocity in one of the two alternate directions is at least twice as great as in the other direction so that said sieve will travel at a greater speed in one direction than in the other alernate direction.

2. The sifter device of claim 1 wherein the vibrating sieve has a greater speed in the downward direction than in the upward direction; wherein there is a lever arm attached to the elongate axle nearer to one end thereof and extending subsantially normally with respect to said elongate axle, the length of the said lever arm exceeding the height of said at least one lifter bar; wherein the means for imparting oscillatory angular motion to the elo gate axle is applied to said lever arm; and wherein the extend of angular oscillation for the elongate axle is less than about 3. The sifter device of claim 2 wherein each of said support rods is resiliently flexible, the captive ends of said support rods being fixedly attached to the frame member so that the resulting cantilever nature of the resiliently flexible support rods provides the means for limiting the upward direction of travel for said support rods free ends; wherein there is an elongate anchor rod positioned below said support rods nearer to the free ends than to the confined ends, said anchor rod inter secting and attached to said several support rods; wherein the multiaperforate sieve member is pivotably attached to that portion of the frame member that extends along the rearward edge of the sieve; wherein there is a plurality of lifter bars attached at intervals along the elongate axle, the height of the respective lifter bars being substantially equal and the height of each lifter bar exceeding the distance between the elongate axle and the anchor rod whereby said lifter bars are adapted to strike the anchor rod as the elongate axle oscillates about its elongate axis; and wherein the length of said lever arm is at least four times the length of the respective lifter bars.

4. The sifter device of claim 2 wherein the captive ends of the respective support rods are pivotably attached to that portion of the frame that extends along the rearward edge of the sieve; wherein said frame member includes a protruding contour extending above the several support rods adapted to strike said support rods as they are pivoted in the upward direction and wherein the support rods are resiliently attached to the elongate axle so as to provide a means for limiting the upward direction of travel for said support rods free ends; wherein the multi-perforate sieve is pivotably attached to that-portion of the frame member that extends along the rearward edge of thet sieve; and wherein the length of said lever arm is at least four time the length of said at least one lifter bar.

5. The sifter device of claim 3 wherein the means for imparting oscillatory angular movement to the elongate axle comprises a powered cam bearing against said lever arm, the cam contour including a discontinuity, the cam contour being convexly curved on one side of said discontinuity and being flatter on the other side of said discontinuity.

6. The sifter device of claim 4 wherein the means for imparting oscillatory angular movement to the elongate axle comprises a powered cam bearing against said lever arm, the cam contour including a discontinuity, the cam contour being convexly curved on one side of said discontinuity and being flatter on the other side of said discontinuity.

7. The sifter device of claim 5 wherein the lever arm is located beyond the lateral confines of the multi-perforate sieve.

8. The sifter device of claim 2 in combination with an upright portable hopper to provide a grain cleaner device so as to separate dirt and other foreign matter from farinaceous grain, said upright portable hopper comprising an upper bin communicating with a lower bin, the upper bin being forwardly offset with respect to the lower bin, said upper bin having an upper opening to provide an inlet for the mixture of grain and foreign matter, said lower bin having a bottom panel that slopes obliquely downwardly and forwardly, said bottom panel having a central opening, said lower bin having an opening at the forward portion to provide an oulet for the cleaned grain, the multi-perforate sieve portion of the sifter device being positioned within the central opening of the lower bin sloping bottom panel so as to substantially cover said central opening, the confined ends of the several support rods being attached to the rearward portion of the lower bin so that the support rods free ends extend toward the forward portion of the lower bin, the elongate axle portion of the sifter device being revolvably attached to the lower side of the lower bin bottom panel, the lever arm being located beyond the confines of the lower bin.

9. The sifter device of claim 8 wherein the upper opening of the upper bin is horizontally disposed to provide a top inlet opening for the hopper; wherein the grain outlet for the lower bin forward portion is substantially vertically disposed; wherein a revolvable power shaft intersects the lower bin in a direction substantially normal to the support rods, a multi-fin paddle wheel attached in fixed rotational relationship with respect to said revolvable power shaft, said multi-fin paddle wheel being disposed within the lower bin; wherein the upper bin includes a chute-like portion extending rearwardly of the paddle wheel vertical axis; wherein there are throat control means to control the amount of grain moving from the upper bin to the lower bin; wherein the lower bin has a pair of opposed wheels to render the hopper portable; wherein the power shaft carries a cam externally of the lower bin, said cam bearing continuously against the lever arm, the cam contour comprising a pair of discontinuities, the cam contour being convexly curved immediately adjacent to one side each discontinuity and being flatter on the other side of each discontinuity, the convexly curved and the flatter portions being positioned alternately about the cam contour.

References Cited UNITED STATES PATENTS 237,162 2/1881 Brown 209246 878,728 2/1908 Harrop 209347 X 1,397,340 11/1921 Sturtevant 209310 X 1,488,724 4/1924 Wilson 209349 X 1,555,128 9/1925 Lipscomb et al. 209349 1,685,512 9/1928 Varusky 209246 1,774,893 9/1930 Krider 209349 X 3,307,698 3/1967 Hatfner 209344 X HARRY B. THORNTON, Primary Examiner.

TIM R. MILES, Assistant Examiner. 

1. A SIFTER DEVICE INCLUDING A NON-VERTICAL MULTI-PERFORATE SUBSTANTIALLY PLANAR SIEVE COMPONENT, SAID SIEVE COMPONENT BEING ADAPTED TO VIBRATE IN A DIRECTION SUBSTANTIALLY NORMAL TO THE PLANE THEREOF, THE VIBRATING SIEVE HAVING A GREATER VIBRATIONAL SPEED IN ONE DIRECTION THAN IN THE OTHER ALTERNATE DIRECTION, SAID SIFTER DEVICE COMPRISING: (A) A SUBSTANTIALLY PLANAR NON-VERTICAL MULTI-PERFORATE SIEVE HAVING AN UPPER SURFACE, A LOWER SURFACE, A FORWARD EDGE, A REARWARD EDGE, A FIRST SIDEWARD EDGE, A SECOND SIDEWARD EDGE, AND A TRANSVERSE AXIS LOCATED BETWEEN THE FIRST AND SECOND SIDEWARD EDGES, SAID AXIS ALSO EXTENDING BETWEEN THE SIEVE FORWARD AND REARWARD EDGES, (B) A FRAME MEMBER, A PORTION OF WHICH EXTENDS ALONG THE REARWARD EDGE OF THE MULTI-PERFORATE SIEVE, (C) A PLURALITY OF SUBSTANTIALLY PARALLEL SUPPORT RODS POSITIONED BELOW THE LOWER SURFACE OF SAID MULTIPERFORATE SIEVE PARALLEL TO THE LOWER SURFACE AND TO THE TRANSVERSE AXIS OF SAID SIEVE, SAID OF SAID SUPPORT RODS HAVING A CONFINED END AND A FREE END, THE CONFINED ENDS OF THE SEVERAL SUPPORT RODS BEING ATTACHED TO THAT PORTION OF THE FRAME MEMBER THAT EXTENDS ALONG THE REARWARD EDGE OF THE MULTI-PERFORATE SIEVE, THE FREE ENDS OF SAID SUPPORT RODS BEING FREE TO MOVE IN THE UPWARD DIRECTION, MEANS TO LIMIT THE UPWARD DIRECTION OF TRAVEL FOR SAID SUPPORT RODS FREE ENDS, SAID MULTI-PERFORATE SIEVE BEING ATTACHED TO SAID SUPPORT RODS, (D) AN ELONGATE AXLE THAT IS REVOLVABLY ATTACHED TO THE SAID FRAME MEMBER, SAID ELONGATE AXLE BEING POSITIONED BELOW AND SUBSTANTIALLY PARALLEL TO THE MULTIPERFORATE SIEVE, SAID ELONGATE AXLE BEING SUBSTANTIALLY NORMAL TO THE SUPPORT RODS AND TO THE SIEVE TRANSVERSE AXIS, (E) AT LEAST ONE LIFTER BAR ATTACHED ALONG THE LENGTH OF THE ELONGATE AXLE AND EXTENDING IN HEIGHT TOWARD THE SAID SUPPORT RODS SO THAT SAID AT LEAST ONE LIFTER BAR WILL IMPART UPWARD MOTION TO THE SUPPORT RODS AND SIEVE WHEN THE ELONGATE AXLE REVOLVES ABOUT ITS ELONGATE AXIS, (F) MEANS FOR IMPARTING OSCILLATORY ANGULAR MOVEMENT TO SAID ELONGATE AXLE ABOUT ITS ELONGATE AXIS SUCH THAT THE EXTENT OF ANGULAR OSCILLATION IS LESS THAN 270 DEGREES AND THE ANGULAR VELOCITY IN ONE OF THE TWO ALTERNATE DIRECTIONS IS AT LEAST TWICE AS GREAT AS IN THE OTHER DIRECTION SO THAT SAID SIEVE WILL TRAVEL AT A GREATER SPEED IN ONE DIRECTION THAT IN THE OTHER ALTERNATE DIRECTION. 